Affinity probes, such as monoclonal antibodies, are one of the most powerful tools in the study of biology. Although the use of antibodies in bioanalytical assays has prevailed for over half a century, they do not fulfill the requirements needed for high-throughput profiling of the human proteome. Several synthetic affinity reagents, such as recombinant and engineered antibodies or nucleic acid aptamers, are generated through advancing bioengineering technologies. Among these new affinity reagents are aptamers: single stranded oligonucleotides whose structures that result from unique folding patterns allow them to bind to particular targets with high affinity.
However, affinity interaction alone is not always sufficient for the discovery of high-affinity aptamers and further the development of sensitive assays.